Commonly fluoroalkyl phosphate surfactants and surface treatment agents contain multiple fluorochemical chains, containing a higher percentage of fluorine at a given concentration and are typically used because they are thought to provide better performance. However, the fluorinated starting materials are more expensive and in short supply. Reduction of the amount of the fluorinated starting material in these surfactants while maintaining the same or better performance is desirable. Reducing the amount of the fluorinated starting component needed would not only reduce the cost, but also shorten the cycle time as fewer steps are needed in the production of the surfactants and less energy is required. Reducing the fluorine content would reduce the cost, but it is necessary to maintain product performance.
Brace and Mackenzie, in U.S. Pat. No. 3,083,224, describe mixed fluoroalkyl phosphates having the formula [CmF2m+1CnH2nO]yPO(OM)3-y where m is 4 to 12, n is 1 to 16, and y is averaged to be 1.0 to 2.5. Brace and Mackenze describe their use as an oil repellent, particularly when y is 2.
Phosphate surfactants having ammonium as a counter ion can potentially release ammonia into the environment. Alternate counter ions need to be able to provide a stable surfactant, while also providing no adverse effects to the surfactant performance.
It is desirable to improve surfactant performance, in particular lowering of surface tension in coating compositions while using less fluorinated starting materials and a counter ion other than simple ammonium compounds. It is also desirable to impart improved surface effects to coated surfaces. The present invention provides a method to increase surfactant performance and to impart improved surface effects to a coated surface while utilizing less fluorinated starting material.